The present application relates to an electric circuit, a charge control device, a charge system, and a control method, and more particularly, to an electric circuit, a charge control device, a charge system, and a control method, which are configured to realize a circuit that drives a semiconductor switch with a relatively simple configuration.
In recent years, as an important point in increasing the availability of electric vehicles or a smart grid, the development of a relatively safer and more convenient secondary battery is expected.
Generally, a relay that opens and closes by physically moving a contact using an electromagnet is inserted in a power line that charges and discharges the secondary battery, and thereby powering on and off is controlled (refer to Japanese Unexamined Patent Application Publication Nos. 2010-141957, 2009-100644, 2009-240081, and 2009-183025). For the control of powering on and off, a semiconductor switch or the like is used, in addition to the relay.
In regard to the relay, a high breakdown voltage relay is large in a scale and is expensive. On the contrary, in a case where a semiconductor switch such as an FET (Field Effect Transistor) is inserted to a power line on the a reference potential side (ground side: in the following description, for example, a negative side), and a control of powering on and off is performed by the semiconductor switch, this can be realized with a small size and at a low cost.